128 Bit Encryption with WinXP….

I have tried and tried to get my wireless access pcmcia card to use 128Bit Encryption.

When I go to the settings it only has options for 104Bit, someone mentioned there was a fix for this in XP?
When I put the card in a 2000 machine I get the option to enter the 128Bit key straight away no probs. I have looked through the XP Help but cant seem to find anything.